DE1501328A1 - Method and device for quick freezing individual food items - Google Patents

Description

PATENTANWALT Λ A JfB V Λ β U-XICtB VTALL 41 ■ fIBMBCl ¹ M 7ί is UMD Jl (1 U

Expl

Thermice Corporation

1429 Walnut Street

Philadelphia, Pennsylvania

19 102 / USA June 21, 1965

Method and device for quick freezing individual food items

The invention relates to the freezing of food for storage purposes. In particular, it relates to a method and a device for quick freezing individual or separate food items in such a way that the Food items remain separate and can be separated from each other and not into one after the freezing process Blook or a mass are frozen together

In order to successfully freeze a number of different types of food, it is necessary to carry out freezing in a rapid manner. One reason for this is that the dimensions of the The ice crystals formed by the water content of the food are related to the freezing time «!. The faster the freezing takes place, the smaller the ice crystals and the less the cell structure of the food is damaged. Examples of foods that are very delicate in relation to the dimensions of the ice crystals, and for which rapid freezing is therefore important, tomato slices are

Gooseberries and cherries.

Another factor that may require rapid freezing of some foods is their presence Rasoh-acting enzymes that can change the taste of the food very quickly. When the freezing rasoh enough occurs, the action of these enzymes is stopped and the undesirable change in taste does not occur. An example One such food that is likely to freeze rapidly because of its sensitivity to taste is corn.

For some foods, there is a reacher freezing process Desirable because their structure is fragile are. The rapid freezing of such food items creates a strong frozen exterior which makes it possible to continue handling and processing the food item despite its inherently fragile nature. Examples of these foods are ripe, peeled bananas and onion rings

One of the common freezing techniques is to freeze the food Frozen in Paokungeη, in which the various food items that make up the package are frozen together or baked. Even if the consumer cooks only part of the food contained in the package or wants to eat, he must thaw the entire package in order to separate the XeIl required for use from the rest. By Remaining nutrients! ttelreat cannot reapply with success are frozen and must therefore be consumed relatively quickly.

909028/073 «- 3 -

quemer when the food is frozen in the way that in the pack, the individual items remain separate or easily separable from one another. Palis carried out the freezing if this result is obtained, the consumer can choose that part of the pack that he wishes to use, separate without thawing the rest of the pack.

A technique to freeze individual food items so that that they do not hang together consists in rapid freezing. Rapid freezing is therefore a desirable option Technique also applies to those types of food that are not necessarily affected by relatively slow freezing Suffer harm.

Another problem, which resulted in the freezing technology to inconvenience is that many of the operations used so far are carried out substantially in a batch mode and are difficult associated with the use-to-use auxiliary equipment, such as Gefriersohalen or freezer boxes _o

According to the present invention, there is provided an improved method and apparatus for quick freezing food in which the individual items are kept separate from one another. The invention is most advantageously practiced with a powdered coolant such as granulated dry ice or dry ice snow, although certain aspects of the invention are also useful when using liquid coolants. _{ΛΛΛ Α}

909828/0738

A feature of the present invention is that an improved method and apparatus be created for quick freezing individual or separate food items.

Another feature of the invention is the provision of a Method and device for rapid freezing of food by using the latent heat of evaporation in powder form! Dry egg lake.

Another feature of the present invention is to provide a method and apparatus for the quick freezing of food which is easy to scale can be adapted to a continuous working method and can easily be used in a continuously operating food processing plant

Another feature of the invention is the provision of one Process and a device for the rapid freezing of food, with which even very fragile food can be frozen successfully

Further features and advantages of the invention result from eioh

the following description in conjunction with the drawings.

fig. 1 is a side view of a device according to the invention

Freezer supply,

ο »Flg. 2 shows part of the in FIG

Pig · 1 shown freezer, both the

Simplicity keep some parts left out Bind

Pie fig 3, 4 and 5 aind cut side partial views

similar to Tig. 2 and show other constructions 4e «~ le4l · ·» of the for the Separation and circulation of the coolant used parts of the device.

Pig. Fig. 6 shows a view of one in side elevation and in detail Another embodiment of the invention in which the For the sake of simplicity, some parts have been left out

Pig. 7 is a partial side view taken along line 7-7 of FIG. 6th

You Pig, 8 "to 11, make a number somewhat similar

Cross quits near line 4-4 of the Jig. 1 and show the successive stages of the freezing process according to the invention.

It has been found that the effectiveness of dry ice as a coolant for food items larger than bind than in powdered foods, is increased significantly, when the dry ice is generally in granulated or powdered form and for a short period of time in intimate contact with brought to the food items and then the slight contact is somewhat interrupted. The time-11one sequence the intimate contact of the Trookeneiaea with the food

909828/0731 - «- '

objects and the interruption of contact is appropriate Repeatedly until the food items were frozen are · Duroh repeated exposure of food items or other-sided interruption of contact between With them and the dry ice, the thin layer of gaseous carbon dioxide that is on the point of contact is dissolved between the dry ice and the individual food items. The dissolution of the Gaasohicht is important, because the gas, even though it is cold, has a low heat transfer coefficient and, as an insulating material, is between the food item and the solid carbon dioxide works. The carbon dioxide gas layer inevitably forms as a result of the heat flow from the food items to the solid carbon dioxide or the Trookenelsgranulatf these Heat flow provides the latent heat of vaporization for the carbon dioxide

Since «the above-indicated procedure for increasing the enteohelende Effectiveness of the powdered coolant can be carried out in various ways. The preferred way is in melting the food items with the dry ice and so long with the powdered dry ice to stir until the food items are rotated Your preferred method of overturning can get yourself back in

JEJ can be carried out in different ways. For example, if ea

o> in a concept constructed according to the present invention

oo riohtung is carried out, the circulation consists in that a ° Bed made of powdered dry ice with food items divided on it and in it before yyy and repeated is flipped or turned over to remove the food

would repeatedly hit the dry ice cover and add To expose IrOokenels.

In Pig. 1 is a preferred embodiment of the device · The circulator 10 is rotatable in a frame 11 with the aid of bearing belts 12 which sit in cradles 15 and 14 stored. The frame 11 is provided with a winch 15 which below the entry end of the unit on the legs of the Frame is attached. By changing the setting of the Winch Is it possible to tilt the circulator a little and to change the tilt angle for purposes that will be described later. The circulator is on cradles 13 and 14 by the Motor M-1 via a chain 16 and a circumferential sprocket 17 turned.

At the lower end of the circulator 10, a sleeve 18 is arranged, which surrounds the end of the circulator, but does not rotate with it.

The inlet end of the circulator is shown on the left in FIG. The equipment in the inlet includes a food conveyor 21, which is mounted on the frame 22, and a Trookeneisrne 23 fed by granulated dry ice »the Soslerer is attached to the frame 11 above the inlet end of the circulator 10. As can be seen from Ed. 1, the doer contains a small, essentially lined up container 55, in the bottom of which a doser opening 56 is provided. Am adjustable »dosing valve in the form of a thin metal strip, that slides at the bottom of the container near the opening 56

909828/073 8 - β -

IbUI

let stored allows the cross-section to be changed the opening and thus a change in the throughput.

The Dosltrtr is vtrsshtn with a stirrer 58, which is driven by a motor 14-2. The stirrer is set to rotate slowly in order to prevent the granulated trooks in the doser from coagulating) such caking would interrupt the outflow of trookeneiaea from the opening 26 into the channel 23. At this point it is emphasized that the connection with the Pig. 6 and 7 shown and described Trookenelsdoslerer also in a device of the In the TIg. 1 and 2 can be used, and that the Dos lerer naeh ¹ FIg ₉ 1 also with dtr in MLg. 7 unit can be used «

On the frame 11 is a scraper 25 io mounted that tr eich stretched into the upper part of the circulator. At dtr in The unit shown in 71g · 1 and 2 extends to the scraper throughout the length of the circulator, and it is at both ends attached to the frame. In other embodiments, for example in the Pig. 3, 4 and 5, because of the special equipment provided at the exit end of the circulator, it is desirable that the scraper ends shortly before the exit. In a solo case, the g The scraper is only attached to the frame 11 at the inlet end and JJJ protrudes with a gtwtinsohttn length, for example some dm or

co m, frtltragtnd into dtn ümwälzer.

■ »v». ·

J £ At the exit end of the circulator β 10 is tint food center channel provided in which the food leaving the circulator

medium are directed to the removal conveyor 27 * The The structure of the circulator 10 can best be seen in FIG. The circulator is provided with a lining 30. That Lining is shaped so that the passage through the circulator has a preselected shape. Sioh a polygonal cross has been shown to have a moderate number of sides has, for example as Seohseok or Aohteok. With some Food items are two-shaped in sioh closed curve shapes, for example ellipses. Are also at some types of food items with passageways circular cross-section can also be used. The feed 30 should consist of a material with which the food can come into contact without damage and that the low temperatures prevailing in the circulator can endure without disadvantages. It has been shown that stainless steel meets these requirements very well. Although it is possible to use the chuck 30 It is usually preferable to provide diaphragms and other elements to increase the circulation effect Orifices should not be used, except in the immediate vicinity of the ends of the circulator. There is a reason for this in that a circulator with a rugged interior is more hygienic and easier to clean.

The space between the outer cylindrical sleeve 31 of the circulation 10 and inner liner 30 is preferably covered with an insulating material such as polyurethane foam, which is listed at 32 JJ is indicated, filled out. . ο

Figure 2 also illustrates the nature of the interaction between the JJJ different parts of the device shown in Fig. 1, S From Fig. 2 iBt it can be seen that sioh the

21 extends into the inlet end of the circulation passage, so that it feeds the food items into the circulating passage and them into the dry ice bed formed there settles. Pig. 2 also shows that the trooke ice sheet 23 so it is appropriate that they put the dry ice in the entry end of the circulation passage enters in countercurrent with the food items and thereby continuously the rearmost

in the

Part of the / inside of the circulator maintained dry ice bed builds up.

As will be discussed in detail below , almost all of the powdered dry ice remains in a food-grade freezer bed during the operations in the lower part of the circulator. over most of the Length of the circulator, there is little or no tendency for the Trooke ice powder to adhere to the scraper and thus during the rotation of the circulator in the upper part of the circulator to be carried. However, the inlet end of the circulator is relatively warmer, and the atmosphere in this area is relatively more humid than in the rest of the Umwälzeraj so any verbaoken will be of dry ice as well as the formation of water ice on the Walls of the circulator mainly near the inlet end focus. The purpose of the scraper 25 is to

ο Dry ice and water ice that occasionally adheres to putter 30 and is carried in the upper part of the Umwälserdurohganges, ^ - ^ to replace. When the Umwalzerdurohgang crosses a polygon

, j, for example the hexagonal one shown in flg »Cross-section, the wiper 25 is preferably with a

Distance from the Aohse of the passage arranged, which is approximately the same

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The smallest radius of the polygon is · In this way the scraper touches each side of the putter 30 once during each Revolution·

Another step that is desired to prevent the attachment of [To exclude dry ice or other material near the inlet end of the circulation means that a part of the putter 30 is provided with a coating or a coating made of polytetrafluoroethylene (Teflon). In Pig · 2 1st a special coating 34 made of Teflon is shown, which sioh from the inlet end a few dm or m down into the Circulator streamed into it.

The pulverized dry ice can basically be fed into the circulator in two different porms. Becomes a porm commonly called "granulated dry ice". Granulated Dry ice is made by pulverizing dry ice blocks using a standard type of trooke ice pulverizing unit, such as a scraper. PUr the so produced Particle size between 0.15 and 0.2 mm is desired. It is preferred to avoid large particles because they do not so without further ado with the food items Stepping in contact and because of their dimensions cannot easily be separated from the food items. Granulated · dry ice is useful in many food freezers made in accordance with the present invention can be operated in a handy block or cake form related and stored and depending on the use · parts pulverized according to the needs arising during the operations can be. If granulated dry ice is used, then

809828/0738. " ¹² "

Measure it into the circulator with the help of the slowly rotating dry ice dispenser 24 _o The other common form of powdered dry ice is called "Irockeneissohn-ee". The snow is produced by the fact that liquid carbon dioxide is expanded through a pressure reducing nozzle or opening in order to achieve a phase transition from liquid carbon dioxide at high pressure to solid carbon dioxide in the form of snow and carbon dioxide gas. the snow can be formed directly in the circulator 10 by directing gravelly carbon dioxide to an opening located directly on the inside of the inlet end of the circulator.

Bas during the freezing process inside the circulation era evolved gaseous carbon dioxide escapes from the circulator through both the inlet and the outlet end This is not a serious problem in a well ventilated area,

FIGS. 2 to 5 show different embodiments of Circulatory devices for the return of the excess Part of the dry ice from the outlet end of the circulator back into the circulator. The cycle process can too

ο be carried out in a different way. In the one shown in FIG

^{In the} embodiment, the circulation passage at aφinem outlet ^ the end provided with a sieve wall 33. The Masohenweit · des

ο ■

..v sieve is chosen so that the dry egg powder through the sieve

approx. .

m hindu falls, while the experience middle objects do not you can fall flat. In this way the food

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medium objects are separated from the dry ice. There is preferably a sleeve 18 around the end part of the circulator stored, which has a sieve wall to the from the circulator to collect escaping dry ice and pass it through the sieve. The trooke ice collected in the envelope 18 falls through the open bottom of the envelope into the collecting container 28. The Trooke ice accumulated in this way in the jarring container 28 is returned to the trooke ice dispenser 24 at suitable intervals.

The one in Pig. 3 shown modified embodiment

the is similar to / of FIG. 2, but the sleeve 18 is on the ground closed, and a fan 19 is mounted on the bottom of the case. The fan 19 causes a continuous return in that it removes the trooke ice that has accumulated in the cover blows into a feed or return line 20, which sioh The conveyor line 20 preferably extends so far into the circulator in that the returned trooke ice is blown out at a point which is approximately in the middle between the ends of the Umwälzerθ lies.

A slightly different arrangement for the recirculation is shown in 71g x 4. Again there is a sieve for separation used, but the arrangement of the separator is changed. A sieve 40 is attached to the outlet end of the circulator so that that it strikes into the passage. At the end of A set of apertures 41 is provided in the passage at each angle of the polygonal passage Aperture attached. As from Flg. 4 can be seen, represent the

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Blind flat plates that extend into the passage. When the circulator is rotated, the shutters pick up a segment of the trooke ice bed containing the food items and raise it to a position slightly above the sieve 40 Sieve 40. The powdery dry ice flows down through the sieve 40 ₉ while the food items cannot pass through the sieve. In order to make this separation even more effective, customary power-operated means for the averaging of the sieve 40 can be provided. The food items slide down on the inclined sieve 40 onto the removal conveyor 27. The dry ice that has fallen through the sieve 40 collects on the HUokfUhrförderer 42. The RUokfUhrförderer 42 is cantilevered so that it is above the dry bed containing the food items upstream into the passage to the Uokerstreokt. The conveyor ends at a predetermined point within the circulator and discharges the returned dry ice near the bottom onto the dry ice bed present within the circulator.

The 71g. The device shown in Figure 5 is similar to that of the Tig. 4, however, the circulator has a generally cylindrical cross-section. Again, apertures are provided at the outlet end of the circulator used · In Fig. 5 they are denoted by 41a. From the figure it can be seen that the diaphragms are slightly longer than in the Embodiment according to Fig. 4, and that the downstream Sections of the bezels with a slight curvature over the

909828/0738 -15.-

Surface of the circulator run. The calibrate the ends of the Food items and dry ice items approaching the unit are prevented by the barrier or end plate 59 from flowing out. Instead, they are from the diaphragms 41a raised. The shutters raise the food items and dry ice to a slightly above screen 40a and 40a the groove 60 located at the height. There the food items and dry ice fall off the panel and get there depending on their distance from the end of the circulator to the channel or the sieve 40a. The food and trook ice cream falling onto the chute 60 slide down onto the Sieve 40a · The trooke ice falls through the sieve 40a onto the circulating fodder 30. The curved parts of the ends 41a tend to somewhat induce the dry ice to migrate back upstream in the stream tumbler. The food items leave the circulator on the sieve 40 *.

The forms of execution of those used for circular performance According to the invention devices that are used in conjunction with the Figures 3, 4 and 5 provide countercurrent recycle. If so desired, they can be modified to that they give a direct current feedback, namely in that the return funds are arranged so that they feed into the inlet end of the circulator or that Release trooke ice, for example, at the entry end into the channel 23. In general, it is desirable that the returned

Trooke ice on one located approximately in the middle of the circulator

Has

To give up the position because experience has shown that this is the case The area is where the powdered dry ice making up the freezing bed 50 settles in the absence of recycle eu begins to dilute. 909828/0738

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- "ίο - lÖLH όά \ 5

The following is to be found in the Pig. 6 and 7 illustrated embodiment of the invention will be described. How on was already mentioned above, the dry ice dispenser shown in these figures cannot only be used with the one in Pig. 6th shown unit, but also for units in Pig. 1 can be used. The dry ice dispenser 24a after Pig. 6 is essentially barrel-shaped, and the passport 61 is rotatably mounted at an angle to the horizontal and can be driven by a motor (not shown). The lower end of the pass 61 consists of two segments 62 and 63, the relative angular divisions of which are changed can be to give a feed opening 64 (see Pig. 7) of preselected dimensions. By changing the With the dimensions of this opening, it is possible to change the metered throughput of granulated dry ice « Passport 61 is rotated slowly, and the dry ice falls through the opening 64 with a preselected throughput onto the channel 65.

The one in Pig. The apparatus shown in FIG. 6 incorporates many of the features of those previously described in connection with FIGS Device, however, differs in that the frozen food is at the same ends of the circulator, in which also the unfrozen Food is entered. With such an arrangement ^ the end of the circulator opposite the inlet end oo be essentially closed. This is an advantage because oo it is the number of flow paths for those into the unit incoming heat is reduced. Other advantages of “this type of unit include a simplified circle layout and a more complete utilization of the cold volume

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of the revolutionary. Aue Pig. 6 let to see that the revolutionary 66 has an outer jacket 67, which is covered by insulating material 69 is separated from the inner putter 68. The revolutionary is with With the help of carrying straps 70 rotatably mounted on cradles 71 »Das Putter 68, like putter 30 in Figure 2, is hexagonal Cross-section. The revolutionary is at his when looking at the Pig. 6 on the right-hand end provided with an end ring 72 which is attached to the end of the circulator and which connects to the circulator turns. The hole formed in the end of the circulator through the inner edge of the end ring 72 is for the most part duroh the End disk 73 closed, which is attached to the frame member 74 and does not rotate with the circulator (duroh the disk and a narrow circular slot 80 is formed in the ring). An input conveyor 75 is arranged so that it. Objects into the left-hand end of the Umwälzera and onto the Trooke Ice Bed feeds, which is formed in the circulator by the dry ice flowing down in the channel 65. The dry ice bed 76 with the food items therein is substantially similar in shape and puncture to that shown in Pig * 2 Dry ice bed 50.

At the angles 4es polygonal putter 68 are at its right-hand end panels 77 arranged in such a position that they the part of the dry ice bed and the therein the food contained in it that reaches the right-hand end of the circulator. The food thus absorbed is deposited on the channel 78, which extends from the End plate 73 self-supporting in the right-hand end of the

Arranged in a trek.

909828/0738

A motor M-3 is mounted on the frame 74. He's on a

Shaft 79 connected, which extends through the from the disc 73 and the ring 72 formed circular slot 80 extends to the left-hand end of the circulator 66 and there is mounted in the frame member 80. The shaft 79 carries the return tube 81, which with the help of turnstiles 82 on the Shaft is mounted. Like from Pig. 6 can be seen, the reversing tube 81 is mounted essentially horizontally, although it can also be inclined up or down sohwaoh It is arranged within the circulator 66 so that that it receives food and dry ice from the channel 78 at the right-hand end of the circulator. Inside the Return tube 81 is a substantially helical one Dosing scoop 83 rotatably mounted on the pipe. The wall of the Tube 81 is designed like a sieve at the left-hand end, as shown at 84. On the frame 80 is a Fastened channel 85, which extends into the end of the circulator 66 up to a liner point where they can hold food items, discharged from the end of the return pipe 81 · The chute 85 conveys the frozen food items to the outfeed conveyor 86.

The apparatus of Figure 6 operates generally as followsi The circulator 66 is driven by a chain drive, the

o the sprocket 87 contains, set in rotation. In the to

The left end of the unit is fed dry ice onto the chute 65, and onto the conveyor 75

Food items fed. The food

»Objects and dry ice move duroh in a bed the overturning ztny right-side end, where it is recorded and

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be deposited on the channel 78, which calls them into the return pipe 81. This pipe is made with the help of the motor M-3 rotated slowly, and the dry ice and food items travel to the left through tube 81 and become "Supported in this movement by the shovel 83» Das zum left-hand end of the return tube 81 reaching unused Dry ice falls through the sieve wall of this tube onto the dry ice bed 76, which is moved to the right. On this Way becomes a very simple circus performance of dry ice achieved. The frozen food items separated from the dry ice in this way will fall from the end of the Pipe 81 onto the channel 85 and finally onto the removal conveyor 86.

The operation of the device having the preferred polygonal circulator cross-section can be best when looking at the pig. 8 to 11 are understood} these figures show successive figures in a somewhat mathematical representation Conditions during part of a revolution of the circulator. Have arrangements with other cross-sections generally a similar operation. In order to be able to follow the work processes better, is on the outer housing 31 of the circulator an indicator mark 43 attached. By comparing the relative positions of the indicator mark, one can recognize that the circulator 10 during the movement between FIGS. 8 and 11 by an angle A counterclockwise turned.

As can be seen from these figures, the passage of the circulator 10 has a hexagonal shape and the chuck 30

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has six flat sides. The two sides of the lining, those that are most important in the following description are indicated at 44 and 45.

During the rotation of the circulator, a dry ice bed is established within the circulator, in and on the separated Food items are included. The bed is identified by the reference numeral 50 in FIG. 8. In this In the figure, the bed consists of a layer of powdered dry ice that is spread over side 44 and contains various food items 51 »

In Fig. 9 the circulator has been rotated somewhat so that the side 44 is no longer horizontal. The dry ice bed and the food items tend, under the influence of gravity, to seek out the deepest part of the circulator. Therefore, the dry ice and food items attempt downward toward the centerline 52 slide. The food mid-articles have a greater tendency to slide down toward the centerline 52 than that Dry ice. In other words, the dry ice has a greater tendency to be carried upwards by the circulator than the food items. As a result, compared with the state shown in Fig. 8, the structure becomes

o the dry ice bed torn open, and the covering of the to

oo Food items become more or less verro

dwindle brewed.

oo Fig. 10 shows the next step in the sequence of operations. The act of turning the bed over is in itself

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completely drained, and the bed lies with a new structure at the apex between sides 44 and 45 · Die Food items 51 are in turn covered by the bed of powdered dry ice ", but the gas layer, which tends to isolate the food from the dry ice is during the rollover or tear or The handling process in which the food items were temporarily unchecked has been dissolved.

If the circulator continues to rotate, the state shown in Pig, 11 is established. Again it can be seen that the bed 50 is ruptured when the dry ice and food items move under the influence of the Move gravity toward centerline 52 with varying degrees of ease. Again, the dry ice tends to being carried up by the wall of the circulator as the food items. The one shown in FIG Situation represents an intermediate state of a circulation process, at the end of which the bed is again the one in Pig. 8 shown Has structure.

In summary it can be said that the one carried out by the overthrower The operation consists of the dry ice bed, in

^ _{0 to} which and on which the food items contain

to are to turn over repeatedly in the transverse direction, taking the bed

ro repeated from the in Pig. 8 into the position shown in Pig. oo

^ 10 shown position and backwards. ο

-4
CO
OO

.Significant changes in the Variable and the dimensions of the facility

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\ J £ .0

are possible without departing from the scope of the invention. However, it can be certain "preferred measures indicate. Experience has shown, a residence time in the circulation pump of about 3 minutes desired for the rapid freezing of most food and for its cooling up to an intended final temperature of about -32 ⁰ C that is · In a Given a given circulator, an increase in the inclination of the circulator tends to reduce the dwell time of the food items therein, because the food items then slide faster through the circulator under the influence of gravity. Some foods slide more easily than others, and it has been found that the incline of the circulator represents that variable, the change of which is the most convenient measure for adapting to differences in the sliding properties of the food Minute turns, for a gradient between 15 and 20 ° the nominal residence time of 3 minutes.

The speed of the circulator can be changed within wide limits «A very satisfactory * speed is in the Close to 10 revolutions per minute. Within certain limits, an increase in the speed leads to a reduction in the Dwell time in the circulator and a reduction in the dwell time that is required for a preselected To reach the final temperature, because the freezer bed is circulated more frequently in the unit of time. With certain foods, however, a high speed can damage the

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Foods lead before the frozen outward appearance The protective layer has completely formed, and if the speed is increased too much, the circulation becomes less effective of the bed is actually lowered because the effect of centrifugal force removes the dry ice and the food items be held against the wall during the entire rotation.

The length and diameter of the circulator can be varied considerably. In general, one allows Increasing the length results in a greater throughput with the same dwell time. The diameter should be chosen so that the sides of the polygon form a freezer bed of suitable width for the food items to be processed. With a very large number of foods sioh has in an arrangement constructed according to FIG. 1 with a Circulator length of around 3 m and a diameter of around 30 cm with a nominal throughput of around 450 kg per hour a residence time of 3 minutes.

In the preferred mode of operation, the device should be operated with an excess of dry ice generally it is desirable to be about 2 to 3 times in the circulator to maintain the amount of dry ice that is theoretically required to keep that in the circulator Cool down to the desired temperature in any given time. In the interpretation only the latent heat of evaporation of dry ice taken into account because the heat capacity of the circulation process

formed gaseous carbon dioxide only a small contribution ο 909828/0738 _ _9ά __

supplies for freezing,

Ea has been shown that if the input durations of Food and powdered dry ice are adjusted so that for each kg of food about 3/4 "to 1 kg Dry ice are fed in and at the same time essentially all of the appearing at the outlet end of the circulator The amount of dry ice returned in the circuit is the prescribed preferred state is maintained.

CO O OD OO

Claims (10)

DR. ING. H. NEGENDANR PATENTANWALT "] 5Q-J 328 HAMBÜHOSe- NBUKH WALL · 41 · FJS H N H U K 3U 74 28 U N D 3Θ 41 IB SBOKIlAPATBKT Thermice Corporation Walnut Street Philadelphia, Pennsylvania 102 / USA June 21, 1965 patent claims 1. Method of cooling a plurality of individual food items by carbon dioxide, characterized by the following steps » a) Formation of a moving stream of food items by feeding the food items into an entrance area, conveying them to an exit area and removal from the exit area, wherein during at least part of the conveyance to the Exit area by mixing the stream of food items with particles of solid Carbon dioxide a moving bed of intimately mixed particles of solid carbon dioxide and individual food objects is formed in which the particles and the objects in immediate Be in direct contact with one another, and b) repeated tearing open of the bed and repeated restoration of direct contact between ^ a the particles and the individual food items 0 »stands so that it is on the surface of the individual Layer of gas- «6 shaped carbon dioxide repeatedly dissolved and the direct heat transfer from the food items is relieved to solid carbon dioxide, 2. The method according to claim 1, characterized in that the moving stream of food items on an inclined path by gravity slides down from the entrance area to the exit area, and that the repeated tearing open of the "moving bed is achieved by repeatedly rolling over the bed in the transverse direction . 3ο method according to claim 1, characterized in that the amount of solid carbon dioxide particles mixed with the flow of food items, is greater than the amount required to cool the food items as desired, and that the excess of carbon dioxide particles in the exit area is separated from the food items and in the circuit is returned to the solid carbon dioxide particles mixed with the moving stream, 4, device for performing the method according to a of claims 1 to 3 »characterized by a circulator in which an elongated passage is provided, ο feed means for feeding in nutrients co objects and solid carbon dioxide particles with a ^ Particle size that is small compared to the dimensions of the ^ j food items is, in the passage, around oö in it the bed of mixed up food items and to form carbon dioxide particles, it and drive means for rotating the circulator by one axis parallel to the passage, the circulator being inclined at an angle to the horizontal so that the food items fed into it and Carbon dioxide particles move down the passage under the influence of gravity as the circulator rotates move to the bottom of the circulator. 5. Apparatus according to claim 4, characterized by within of the passage arranged return conveying. Which a an input end located near the lower end of the circulator and an input end located near the upper end of the circulator Have output end, arranged near the lower end of the circulator transfer means for transferring the lower End of the circulator incoming mixture to the input end of the return conveying means, and delivery means arranged at the exit end of the return conveying means for delivery of the food items conveyed out of the device by the return conveying means. 6. Apparatus according to claim 4 or 5, characterized by separating means arranged at the lower end of the passage to separate the solid carbon dioxide particles from the food items. 7. Device according to one of claims 4 to 6, daduroh characterized in that the lower end of the circulator is closed is. '-:. 8. Apparatus according to claim 6, · characterized in that 9 0 9 8 2 8/0738 - 4 - the lower end of the circulator is open that the separating means through a sieve separator attached to the open end are shown, the Masohen size is chosen so that the particles, but not the currency items can pass through, and that output means are provided and arranged so that they are of food items separated by the separating means can receive and deliver from the device. 9. Apparatus according to claim 6 or 8, characterized in that the separating means has a perforated wall part of the Have circulator at the lower end thereof, which is designed so that the solid carbon dioxide particles, but not the food items can pass through it, that a collecting sleeve to catch the through the perforated wall part penetrated particles provided is, and that feed means for reintroduction the collected particles are provided in the circulator, 10. Apparatus according to claim 6, θ or 9, characterized by Means for transporting the solid carbon dioxide particles separated from the food items upstream and feed them back into bed. 90982 8/0738